The discus throw is an event in track and field athletic competitions, in which an athlete throws a heavy disc, typically called a discus, in an attempt to mark a farther distance than his or her competitors. The discus throw is an ancient sport which can be dated back at least to 708 BC. Today, the discus throw is a part of most modern track and field meets at all levels of competition and is a sport which is particularly noted as part of the Olympic Games. In ancient Greece, discus throwing was considered the paramount event of the Olympic games.
The discus 10, the object to be thrown, is a heavy lenticular-shaped disc that is convex shaped. The discus typically has a weight of 2 kilograms (about 4 pounds and 7 ounces) and a diameter of 220 millimeter (about 8.66 inches) for the men's events, and a weight of 1 kilogram (about 2 pounds and 3 ounces) and diameter of 181 millimeter (about 7.17 inches) for the women's events. In U.S. high school track and field events, boys often throw a discus weighing 1.616 kilograms (about 3 pounds and 9 ounces) and the girls throw the 1 kilogram (about 2.2 pounds) women's discus. The discus usually has sides made of rubber, plastic, wood, or metal with a metal rim and a metal core to attain the weight. A discus with more weight in the rim produces greater angular momentum for any given spin rate, and thus more stability, although it is more difficult to throw. A discus made of solid rubber is often used in high school either in competition or practice because it is less expensive to purchase, more durable, and easier to learn to throw (due to its more equal distribution of weight, as opposed to the heavy rim weight of the metal rim/core discus).
To make a throw, the competitor starts in a slightly recessed concrete-surfaced circle having a diameter of 2.5 meters (about 8 feet and 2½ inches). The discus thrower typically takes an initial stance facing away from the direction of the throw. The discus thrower then spins counter-clockwise (for right-handers) around one and a half times through the circle to build momentum, then releases the discus. The discus must land within a 34.92-degree arc extending from the circle and marked by lines on the landing zone. The distance from the front edge of the circle to where the discus lands is measured. The competitor's best throw from the allocated number of throws, typically three to six, is recorded, and the competitor who legally throws the discus the farthest is declared the winner.
The basic motion is a forehanded sidearm movement. The discus is spun off the index finger or the middle finger of the throwing hand. In flight, the discus spins clockwise when viewed from above for a right-handed thrower, and counter-clockwise for a left-handed thrower. As well as achieving maximum momentum in the discus upon throwing, the discus' distance is also determined by the trajectory imparted by the thrower, as well as the aerodynamic behavior of the discus. Generally, throws into a moderate headwind achieve the maximum distance. Also, a faster-spinning discus imparts greater gyroscopic stability.
The technique of discus throwing is quite difficult to master and needs lots of experience to perfect. As a result, discus throwers must spend much time practicing their throws and, in particular, their throwing motion. Discus throwers often practice their throwing motion over and over without releasing the discus. However, this can be problematic if done in doors, without adequate space, or near other people because it can at times be difficult to maintain a hold on the discus when practicing the throwing motion at full speed and power. As a result various weights or specialty discs are used which include fasteners to secure the specialty discs and or weights to the thrower. These devices, however, can alter the feel and motion of the discus thrower because they are not training with a regulation discus that they must throw at competitions. Accordingly, there is a need for an improved discus training device.